Power control



Jan. 6, 1942. s. M. UDALE 2,259,294

POWER CONTROL Fil ed March 3, 1959 2 Sheet-Sheet 1 'll J a J0 W 1NVENTOR- S. M. UDALE POWER CONTROL Jan. 6, 1942.

Filed Mar h s, 1939 2 Sheets-Sheet 2 IN VENTOR ATTORNEY.

Patented Jan. 6,1942

S na

rowan con-moi.

M. Udale, Detroit, Mich, assignor to George M. Holley and Earl Holley Application March 3, 1939, Serial'lio. 259,493

. p 7 Claims.

The object of this invention is to control the power of an airplane engine by means of 8. limitation to the quantity of fuel that thevengine consumes. By this means every position of the power control establishes a maximum fuel consumption for that position of the power control. If the mixture ratio isqconstant regardless of variations in pitch of propeller or of altitude, the rate of fuel flow is a measure of the rate of air flow, and hence is a measure of power development.

I have discovered that a governor responsive to the rate of flow of fuel could be used to control the rate of flow of air, and hence the power developed. I further discovered that if I controlled the governor manually, then at any given position of the control of the fuel there will be a corresponding rate of air flow and hence a corresponding power developed. By this means, a-

Figure 1 shows 'myinvention applied to a throttle controlled carburetor in which a servo motor is shown, so that this device may overcome the friction of the carburetor throttles.

Figure 2 shows the relation of the fuel control I to the means for maintaining the mixture ratio constant through variations in altitude and propeller pitch.

In Figures 1- and 2, I8 is the fuel entrance, fuel being supplied under a constant pressure from a mechanically driven pump 86. The fuel flows from Ill-through a ventm'i II, through a second venturi 53, and so to a diaphragm chamber I2. This diaphragm chamber has on each side of it an air chamber I3 and M which control the pressure inside the diaphragm chamber l2, which pressure is also controlled by the spring 8| which draws the two diaphragms 82 and 83 together and thus causes the two fuel needle valves 84 and 85 to seat and shut off the fuel flow from the fuel pump 86 to the fuel chamber l2.

The fuel flows from the diaphragm chamber l2 along the passage l5, past the needle valve it,

to an air and fuel nozzle passage I], which dis-'- charges freely.into the throat formed between the two throttles l8 and Hi. This forms a variable venturi. These throttles are geared together by gears 28 and 2|.

The gear 2| is operated vby a gear 22 mounted on a shaft 23 which is operated by the throttle control lever 31. Hence, as the throttle control passage ll.

l8 and "I8 openand the needle it moves to the right, allowing fuel to pass from the passage l5 into the nozzle passage II.

Thecam 24 mounted on the shaft -23 operates a cam follower 25 mounted on the lever 28 which is connected to the needle'valve 18 so that the throttles and needle valve move in unison as described above. lower 25 in engagement with the cam 24.

The air entrance 21 admits air for idling from the main air entrance 88 to the central passage 28 formed in the needle valve l8 which acts as A passage connects the two chambers l3 and i4 together. -A passage 8| connects both the chambers l3 and. to the vent ring 82 in the air entrance 88 of the carburetor. A restriction 84 limits the amount. of air that can flow from the vent ring 82 into the chambers I3 and I4. On the lower side of the chamber ll, a passage is provided connected by two paths to the nozzle The first 'path is through the chamber 61 which is. connected to the passage 66 through a passage 98 which communicates freely with the passage II. In this chamber 8! is located an aneroidbellows 88 which controls the valve phragm chamber [2. Hence, the area of the slot 10 and the relative area of the restriction 64 determines the pressure in the chambers I 3 and II. In addition to this, a manually controlled valve 19 is provided which applies additional suction to the chambers I3 and s4.

In the position shown, a restriction applies nozzle suction to the two chambers I4 and i3,

lever 31 is rotated anti-clockwise, the two throttles 55 being connected through the passage 18 with the A spring 88 holds the cam folchamber 11. This suction is communicated to the passage I3 which communicates with the passage 85. Obviously the valve I9 may be rotated so as to render the restriction 30 ineffective. In the position shown, however, the restriction 80 is eflective untilthe flow'through the fuel venturi 53 reaches a predetermined value when the depression in the throat of the venturi 53 acting on the diaphragm 13 causes the diaphragm 13 to move to-the left and the pressure of the fuel acting on the diaphragm 14 assists the diaphragm 13 in compressing the spring I3 carrying with it the bridge I2 which carries the valve 1| which closes the air exit through the passage IS. The diaphragm I4 responds; to the pressure of the fuel in the entrance to the venturi I3. Hence the pressure drop in the venturi 53 is the operating means which operates the valve 1| and when the value of the flow through 53 reaches a predetermined value set by the stiffness of the spring 15, the valve closes the entrance to the passage I3 and thus the orifice 83 immediately becomes inoperative and the mixture ratio immediately becomes richer. At the same time, the fuel flowing through 53 causes the needle valve 52 to move to the left, the chamber 54 being subiected to the suction in the throat'of the venturi 53, the needle valve 52 moves to the left compressing the spring 55 and admitting fuel from the entrance to the venturi 53 to the passage 53.

' r The fuel passage 53 is freely vented to the atand is operated by a throttle controlled link 34,

Figure 1.

The passage 41 connects'the entrance of the throat of the venturi II to the servo mechanism shown in the upper left hand corner of Figure 1. The pipe 48 connects this mechanism with the depression in the throat of the venturi When the flow at any throttle position exceeds a certain value, the diaphragm 46 is moved against the pressure of the spring This diaphragm 43 carries the valve rod 45 which controls the servo mechanism. The valves 43 and 44 control the passages 4| and 42, and when an excessive amount of fuel is taken at any given throttle position through the venturi I, the diaphragm 46 moves down and with it the valve rod 45, responsive to the pressure differential in the venturi I This motion admits oil pressure from the passage 49 to the underside of the piston 39 in the cylinder 40. This lifts the piston 39 and carries with it the link 38. This link 38 is connected to the toggle consisting of the brokenlinks 35, 36, which make the broken link connection between the manually operated throttle lever 32. and the automatically operated throttle lever 31. Hence it follows that the throttle will be automatically closed when the fuel exceeds the flow determined by the position of the throttle lever 32 and of the needle 30 in,

the throat of the venturi H. The position of the needle 30 with reference to the throttle lever 32 is determined by the link 3| which may be connected in different positions to the lever 32.

The lever 32 is shown in two p sitions. The

position shown in full lines correspondsto the idlingposition and the open throttle position is shown by broken lines. In the latter position the throttle lever 31 connected to the throttles l4, |9 through the gearing is shown in two positions, both positions being shown in broken lines. In the first the throttles are half open corresponding to the reduced charge which is absolutely necessary when near the sea level to prevent the wrecking of the engine by excessive power In the other position the throttles are wide open and the broken links of the toggle 35, 33 are shown in line with each other, so that the throttles are opened wide enough to permit the engine to obtain the maximum amount of air available, which is a necessary condition at all altitudes above say 10,000 feet.

The location of the pin uniting the three links 3!. 3C and 31 is marked A when the manually controlled throttle lever 32 is closed and the throttles are closed. It is marked B in the second location when the manually controlled throttle lever 32 is open and the throttles are only half opened which corresponds to maximum power near the ground. The third location is marked 0 when th manually controlled throttle lever 32 and the throttles are both wide open, which is the position they assume when maximum power is desired at altitude.

Operation by the spring 5| in Figure 2, the diaphragm 43 descends and the valve 44 admits .oil from the oil pipe 43 to the under side of the piston 33 and thus the link 38 is raised and the broken link, 35, 36 moves to the position shown in full lines, and thereby the throttle control lever 31 is moved clockwise so as to close the throttles and reduce the fuel and air flow. When the velocity of fuel flow falls below the velocity which creates the pressure diflerence determined by the spring 5|, the reverse action takes place and the piston 39 descends, the broken link 3!, 33 straightens out, the throttle lever 31 rotates anticlockwise into the position shown in Figure 1 in broken lines. v'I'hereupon the gear 22 engages with the throttle gears 23, 2| and the throttle I3 is moved in the clockwise direction, the throttle IS in th anti-clockwise direction and the needle I6 is moved to the right until the fuel flow and the air flow increase and a balanceis once more established.

The quantity of fuel flow for any given position of the-throttle is therefore determined by the critical velocity through the venturi l| multiplied by the area between the tapered needle 30 and the throat of the venturi II. By this means, every position of the throttle lever 32 corresponds to some definite maximum fuel flow, and therefore the maximum horsepower is maintained substantially constant at every position of the throttle lever 32.

What I claim is:

1. In a carburetor having a mixing chamber, a fuel supply means discharging therein, a mixture outlet, a throttle valve therein, a throttle two levers together. aut matic mean for reguaeeaeea lating the fuel and air ratio, avariable fuel restriction, control means therefor interconnected with said manually controlled throttle operating lever, means responsive to the pressure difference across said variable fuel restriction adapted to break the toggle when the fuel flow exceeds a predetermined flow, whereby the throttle lever is moved to the partially closed position, the manually controlled throttle operating lever remaining unmoved whenever the fuel flow exvariable orifice.

2. In a carburetor having a mixture chamber, a fuel supply means discharging therein, a mix- .ture outlet, a throttle valve therein, a throttle 1 lever connected thereto, a manually controlled is opened, means responsive to the velocity of flow through said restrictedfuel passage adapted to break the toggle connection whenever the, flow through said fuel restriction exceeds a predetermined value, whereby the throttle lever is moved to the partially closed position, the manually 'controlled throttle operating lever remaining unmoved.

3. A power governor for an internal combustion engine comprising a restricted fuel passageway, a restricted air passageway, throttle means for the air passageway, automatic means responsive to the rate of air flow through said restricted air passage for controlling the fuel flow, meansdirectly responsive to the fuel flow through said restricted fuel passage operatively connected to said throttle valve for restricting and restricting to a like-degree the flow of both fuel and air to the engine when the fuel flow to the engine'exceeds a predetermined maximum.

4. A power governor for, an internal combusceeds the critical fuel flow determined by the tion engine comprising a carburetor, a mixture chamber, a throttle valve therefor, a fuel supply comprising a restricted fuel passageway, means responsive to the air flow to said engine for regulating said fuel supply, means directly responsive to the fuel flow through said restricted fuel passageway operatively connected to said throttle valve so as to limit the rate of air supply to a predetermined maximum corresponding to a predetermined maximum rate of fuel supply.

,5. A power control for an internal combustion engine comprising a carburetor, a mixture chamber, an air entrance leading thereto, a fuel supply regulating means therefor responsive to the air flow, throttling means adapted to control the mixture supply, a restricted fuel passageway.

means directly responsive to the velocity of said fuel supply through said restricted passage, and

operatively connected to said throttle for'limiting the mixture supply to a predetermined maximum.

6. A power governor foran internal combustion engine comprising a mixture chamber having an air supply and a fuel supply, throttling means adapted to control the mixture supply, two restricted passageways, one for the air and one for the fuel, means for regulating said fuel supply by the air flow through its restricted passageway so as to control-the ratio offuelto air, means directly responsive to the fuel flow through its restricted passageway, operatively connectedto said throttling means for limiting the air flow to a predetermined maximumflow.

7. An automatic air and fuel flow throttling means for an internal combustion engine, having automatic means responsive to the rate of air flow and to air density for controlling the ited to. predetermined maximum rates of flow. STANLEY M. UDALE. 

